Impregnation Time Research Articles

Light Olefins Production in a Fixed Bed Reactor Using Alumina Supported Iron-Cobalt-Cerium Oxide Nanocatalysts Prepared by Impregnation Procedure: Effect of Preparation Conditions on Nanocatalyst Performance

In this study, pretreatment conditions such as impregnation time and temperature and drying time and temperature for the production of the iron-cobalt-cerium catalyst with impregnation method as a first step for controlling the synthesis of a new type of three similar metal phase ratio were determined by the Taguchi method. A microtubular fixed bed reactor tested the catalysts' performance under constant conditions according to conversion. The activity and selectivity toward propylene and ethylene have been calculated. The catalyst, which impregnated at 90 °C for 4hr and dried at 120 °C for 24hr, had the best catalytic performance. According to previous studies, the catalyst calcined and the reactor test was performed in the constant and optimum condition such as calcinations in 600 °C for 6hr, reduction with H2 (flow = 30 mL.min-1) for 90 min and P~1atm and also the reaction terms was H2:CO = 1(flow H2 = 37.5 mL.min-1 and CO =37.5 mL.min-1) and p=1bar. Finally, The characterization was done by XRD, SEM, BET, and test on the precursor, optimized catalyst, and optimized catalyst after reactor tests, which all were showed the nanosized catalyst particles.

Visible-light sensitization of anodic tungsten oxide layers with CuWO4

Anodic tungsten oxide is an attractive material for photoelectrochemical water splitting under solar irradiation, however due to several limitations, it absorbs only UV light and, therefore, one of the challenges is to transfer its photoresponse to the visible light region. In this paper, for the first time, it is proposed sensitization of anodic WO3 layers with copper tungstate by a wet impregnation method. The CuWO4–WO3 materials are obtained by immersion of anodic layers in a copper acetate solution and annealing at 500 °C in air atmosphere. As-received materials are characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD), and Raman spectroscopy, Mott–Schottky measurements and photoelectrochemical (PEC) tests. Proposed visible-light sensitization with CuWO4 results in an enhanced photoelectrochemical response to visible light. Moreover, narrowing of the band gap (from 2.88 to 2.47 eV) with a prolonged impregnation time is also observed.

A comparative analysis on the impregnation efficiency of a natural insecticide into polypropylene films by means of batch against semi-continuous techniques using CO2 as solvent

In the present paper the application of the supercritical impregnation technology to the production of a polypropylene (PP) film with insecticides properties has been studied for its potential application in greenhouse facilities. A statistical experimental design was conducted to determine the effect of impregnation time, amount of sample, pressure and temperature on the impregnation loading of pyrethrins in PP. Two experimental procedures have also been evaluated and compared: batch mode and semi-continuous mode. Optimal impregnation time was established at 5 h, but, variation in pyrethrin amounts (1–2 mL) did not show any significant effects on the loading of the sample. On batch mode, the maximum impregnated extract loadings were obtained at 55 °C and 10 MPa. Nevertheless, the batch mode presents some difficulties with regard to scaling up. On the other hand, the semi-continuous mode presented adequate results at 35 °C.

Copper-containing non-woven materials from silk waste

A rational approach to the problem of recycling natural silk processing waste is proposed. Cocooning wastes are processed into needle-punched non-woven material onto which copper nanoparticles are deposited by chemical reduction methods with ascorbic acid from alkaline solutions of copper sulfate. It was shown that, depending on the time of impregnation of the nonwoven material with an alkaline copper solution, sericin, wax and fatty substances are removed from the material, and when impregnated for more than 15 minutes, the amorphous part of fibroin. The amount of copper on the fibrous material can be varied by the conditions of impregnation and washing. The size distribution of copper nanoparticles on the finished material was studied.

The method of RTM process modeling using porous medium

This paper proposes a method to simulate the Resin Transfer Molding process by using Ansys Fluent software. The offered approach permits to calculate impregnation time, to predict dry zones after impregnation and proposes a method to calculate porosity of the final product to predict the mechanical properties. The method is illustrated in the plate resin impregnation case.

Technological Properties of Metallized Carbon Cloth

The results of studying the properties of carbon cloth with a metallic coating and the related coal plastics prepared by a vacuum infusion technology are presented. It is experimentally found that the metallic coating affects the porosity of the cloth, decreasing it by 17% at a coating thickness of 30 nm. The deposition of the metallic coating on the carbon cloth weakly affects on the total impregnation time, decreasing it only by 3.6–4.1%. A comparative analysis of the two technologies by a standard method with the manual fabrication of a vacuum sack and using a test bench with an elastic membrane shows that the use of the test bench makes it possible to accelerate the impregnation process, to decrease the consumption of a binder, and to level the motion front of the binder.

Fast pyrolysis of a SiC-based polymer precursor using a spark plasma sintering apparatus – Effects of heating methods and pyrolysis atmosphere

The effects of heating method on the pyrolysis behavior, crystallinity and ceramic yield of a SiC-based precursor-derived ceramic (PDC) were investigated using commercial allylhydrido-polycarbosilane (AHPCS) precursors, spark plasma sintering (SPS) apparatus and tube furnace. The heating rate of SPS was ten times faster than that of tube furnace. Consequently, the total time of precursor impregnation and pyrolysis (PIP) process decreased distinctly after several PIP cycles. PDCs fabricated by SPS had higher crystallinity than those prepared by tube furnace. The crystallinity of PDCs was 70.4 and 65.1 %, respectively, after the pyrolysis using SPS and tube furnace at 1400℃ for 1h. The highest crystallinity of 82.92 % was achieved after the pyrolysis at 1500℃ for 2h using SPS. The ceramic yield of the precursor was not strongly affected by the heating method. This study provides a promising method for the pyrolysis of ceramic precursors with short processing time and improved thermal stability.

Fe doped-CoB catalysts with phosphoric acid-activated montmorillonite as support for efficient hydrogen production via NaBH4 hydrolysis

In this study, montmorillonite (MMT) clay was modified with different acids to be used as support material. The modified MMT clay was used to obtain hydrogen in the hydrolysis reactions of NaBH4 (NaBH4-HR) as a support material for the Co–B and Co–Fe–B catalyst. During the activation of MMT clay, the effects of different acids, phosphoric acid (H3PO4) concentration, and impregnation time with H3PO4 were investigated. During the hydrogen generation from the NaBH4-HR, effects of Co loading, Fe loading, NaBH4 concentration, temperature and, catalyst durability were investigated. The maximum HGRs for MMT-H3PO4–CoB and MMT-H3PO4–Co–Fe–B treated with 5 M H3PO4 for 7 days were 1869 and 4536 mL/min/gcatalyst, respectively. The activation energies for MMT-H3PO4–CoB and MMT-H3PO4–Co–Fe–B catalyst samples were 49.5 and 38.90 kJ/mol.

Surface functionalization of cellulose with polyethyleneimine and magnetic nanoparticles for efficient removal of anionic dye in wastewater

Activated carbon (AC) has been prevalently used in dye effluent treatment. Nonetheless, the large-scale utilization of AC is normally restricted by its production cost and time-consuming synthesis procedures (carbonization, activation, washing etc.). This study presents a new adsorbent was successfully synthesized via a rapid and straightforward process for removal of anionic dye. The adsorbent was developed from the incorporation of cellulose with polyethyleneimine (PEI) and magnetic nanoparticle (MNP), termed as MCPEI, via crosslinking method. The significant effects of parameters in adsorbent synthesis processes, such as the ratio of materials (cellulose, PEI, MNP), impregnation time and crosslinking degree on the characteristics and synthesis mechanism of MCPEI were investigated. The results reveal that the adsorption of anionic reactive black 5 (RB5) dye onto MCPEI was highly dependent on the ratio of cellulose to PEI (2:1) and MNP dosage of 0.6 g. The surface chemistry of cellulose was successfully modified with PEI and MNP, as depicted by the FTIR, FESEM, EDX analysis and acid-base titration result. The BET analysis showed that the MCPEI adsorbent owned low surface area (1.36 m2/g) and pore volume (0.022 cm3/g) without activation and carbonization. The adsorption efficiency of MCPEI increased with reaction time until equilibrium was accomplished at 180 min. The adsorption of RB5 onto MCPEI was best described as chemisorption with maximum adsorption capacity of 330 mg/g. The excellent adsorption capacity combined with magnetic separation properties makes MCPEI a promising candidate adsorbent for a replacement of commercial AC.

Application of Supercritical Solvent Impregnation for Production of Zeolite Modified Starch-Chitosan Polymers with Antibacterial Properties

In the present study, supercritical solvent impregnation (SSI) has been applied to incorporate thymol into bio-composite polymers as a potential active packaging material. Thymol, a natural component with a proven antimicrobial activity, was successfully impregnated into starch-chitosan (SC) and starch-chitosan-zeolite (SCZ) films using supercritical carbon dioxide (scCO2) as a solvent. Experiments were performed at 35 °C, pressures of 15.5 and 30 MPa, and an impregnation time in the range of 4–24 h. The highest impregnation yields of SC films with starch to chitosan mass ratios of 1:1 and 1:2 were 10.80% and 6.48%, respectively. The addition of natural zeolite (15–60%) significantly increased the loading capacity of films enabling thymol incorporation in a quantity of 16.7–27.3%. FTIR and SEM analyses were applied for the characterization of the films. Mechanical properties and water vapor permeability of films before and after the impregnation were tested as well. Thymol release kinetics in deionized water was followed and modeled by the Korsmeyer-Peppas and Weibull model. SCZ films with thymol loading of approximately 24% exhibited strong antibacterial activity against E. coli and methicillin-resistant Staphylococcus (S.) aureus (MRSA).

Methylene Blue Removal Using Foxtail Palm Fruits as Potential Activated Carbon

Textile industry is commonly use dyes in colouring process which become the major dye wastewater source that leads to serious pollution in the environment. The disposed dyes can lead to serious harm to the water users and life in the aquatic because of the dye properties. Hence, the dye adsorption by activated carbon prepared from foxtail palm fruit was studied. The objectives of this study were: 1) to prepare activated carbon from foxtail fruit palm and 2) to study the effect of contact time, adsorbent dosage and initial concentration of dye usage toward the efficiency of the prepared activated carbon. Nitric acid was used as activating agent in this experiment, with impregnation time of overnight and 500 °C of 2.5 hours carbonization. The adsorption capability of foxtail fruit palm activated carbon as activated carbon was determined with the use of a dye called methylene blue. The results showed that 5 g of activated carbon was used to reduce 97.1% of 2 mg/L methylene blue with 150 minutes contact time. This result aligns with the SEM result which indicated that the produce activated carbon is rich with well-developed and irregular size of pores ranging between 1.585 μm to 7.556 μm. This study indicates that activated carbon from foxtail palm fruits could be utilized as an alternative activated carbon to treat dye wastewater.

Dye removal by activated carbon produced from Agave americana fibers: stochastic isotherm and fractal kinetic studies.

The present work investigates the use of Agave americana fibers (AGF) as a precursor for activated carbon (AC) preparation via chemical activation using phosphoric acid (H3PO4), and the study of the influence of the preparation conditions on the adsorption capacity of the prepared AC toward Alpacide Yellow (AY). The preparation experiments have been conducted at different impregnation ratios: acid/AGF (20 g/1 g, 30 g/1 g, and 40 g/1 g) with varied impregnation times (2 h, 4 h, and 6 h) and at different carbonization temperatures (200 °C, 400 °C, and 600 °C). The impregnation ratio of 40 g/1 g, the impregnation time of 6 h, and the carbonization temperature of 400 °C were selected as the optimal conditions for the preparation of AC with enhanced properties. Despite its low specific surface area (25 m2/g), the prepared AC showed a higher adsorption capacity toward AY (5.71 mg/g) as compared with that of the commercial activated carbon (CC) (5.27 mg/g) which showed a higher specific surface area (825 m2/g). This could be due to the existence of pores and functional groups on the surface of AC, as evidenced by the analysis results of FTIR, DSC, and SEM. The adsorption process was found fast and fractal since it followed the kinetic model of the Brouers-Sotolongo fractal (BSf) (R2 = 0.999), while the mathematical modeling of the adsorption isotherm of AY on the synthesized AC was stochastic since it followed the General Brouers-Sotolongo (GBS) (R2 = 0.999).

Analysis of the non-isothermal resin impregnation process of carbon fibre reinforced composite wing spar structure

This paper presents non-isothermal resin impregnation process of high-performance light weight composite wing spar structure for trainer aircrafts. The manufacturing process of the spar is simulated in PAM-RTM software. In this research developed a reliable model of resin impregnation process simulation to determine the exact infusion time and optimize the resin inlet ports for large scale aircraft structure without using the expensive trial and error experimental approches. The work reported the use of different heating temperature processes to manufacture wing spar from carbon fibre-reinforced epoxy resin matrix composite laminates by using VARI. The influence of heating temperature during the infusion stage on the resin viscosity and impregnation time was analyzed. These results indicate that a proper heating temperature during the infusion process is necessary for quality control and manufacturing time reduction. The error between theoretical simulation and experimental studies is no more than 10%.

Removal of sulfadiazine from aqueous solution by in-situ activated biochar derived from cotton shell

Phosphoric acid is used to in-situ activate biochar pyrolyzed by cotton shells to enhance the adsorption ability of sulfadiazine (SDZ). To confirm the optimum condition, different impregnation ratios and impregnation times were investigated. It was found that the biochar (BC) pyrolyzed under the condition of an impregnation ratio of 2.5 and an impregnation time of 6 h showed the highest performance for the removal of SDZ. The maximum adsorption ability was 86.89 mg/g at a temperature of 298 K. The pseudo-second-order model was used to disclose the adsorption process of SDZ by BCs. The experimental data were described by the Langmuir and Temkin isotherms at different temperatures. It was found that the sorption of SDZ was an exothermic process according to the thermomechanical analysis. The activated BC could be recycled for at least five times with a high removal rate of SDZ. Thus, activated BCs are regarded as promising adsorbents for SDZ removal.

ИССЛЕДОВАНИЕ ПРОЦЕССА ПРОПИТКИ ДРЕВЕСИНЫ БЕРЕЗЫ ОТРАБОТАННЫМ РАСТИТЕЛЬНЫМ МАСЛОМ

Wood is widely used in various industries. However, the inherent ability of natural wood to absorb water and other disadvantages require its modification with various compositions. In the work, the technology of impregnation of birch wood with processed vegetable oil, which remains after cooking, has been studied. Impregnated composition was introduced into pre-prepared wood using the “hot-cold baths” method and subsequent heat treatment of wood impregnated with used sunflower oil. The influence of the main quantitative parameters of the impregnation process on the performance of wood specimens have been made using the design of the experiment according to the Greek-Latin square pattern of the fourth order. The influence of the temperature of the impregnating oil, the time of impregnation, temperature and the duration of the heat treatment on the properties of modified wood has been studied. The properties of birch wood has been evaluated by its water absorption, as well as swelling of specimens in the radial and tangential directions. The regression equations have been obtained. They describe the influence of the main parameters of the impregnatio process with processed sunflower oil on the properties of modified wood. The best conditions for introducing processed sunflower oil into wood have been established. The proposed impregnating composition improves decorative properties of wood. It is odorless and environmentally friendly. It has been shown that treating birch wood with processed vegetable oil makes it possible to obtain modified wood with increased resistance to water

Flame Retardancy of Wood Products by Spreading Concentration and Impregnation Time of Flame Retardant

The flame retardancy, such as carbonized length and area, of four plank type wood products by the spreading concentration and impregnation time of flame retardant were measured according to standard of the Nation Fire Agency in Republic of Korea. To measure the flame retardancy, Korean pine plywood, Japanese larch plywood, Japanese cypress planks, and perforated birch plywood boards were treated with self-development flame retardant by 300 and 500 g/m2 spreading concentration and those were compared with control specimen. In general, the flame retardant performance of wood products improved as the spreading concentration of flame retardant increased. Except for Japanese larch plywood, there was no significant difference in the flame retardant performance by the spreading concentration. The flame retardant performance of perforated birch plywood board was positively correlated up to 60 minutes of impregnation time, but then gradually decreased. These results about the flame retardancy of wood products by spreading concentration and impregnation time were expected to be basic data for improving flame-retardant treated wood.

Determining factors for optimal neuronal and glial Golgi-Cox staining.

Golgi staining allows for the analysis of neuronal arborisations and connections and is considered a powerful tool in basic and clinical neuroscience. The fundamental rules for improving neuronal staining using the Golgi-Cox method are not fully understood; both intrinsic and extrinsic factors may control the staining process. Therefore, various conditions were tested to improve the Golgi-Cox protocol for vibratome-cut rat brain sections. Optimal staining of cortical neurons was achieved after 72h of impregnation. Well-stained neurons in both cortical and subcortical structures were observed after 96h of impregnation. The dendritic arborisation pattern of cortical neurons derived from the 72-h impregnation group was comparable to those of the 96 and 168-h impregnation groups. The entire brain was stained well when the pH of the Golgi-Cox solution was 6.5 and that of the sodium carbonate solution was 11.2. Lack of brain perfusion or perfusion with 0.9% NaCl did not influence optimal neuronal staining. Perfusion with 37% formaldehyde, followed by impregnation, only resulted in glial staining, but perfusion with 4% formaldehyde facilitated both glial and neuronal staining. Whole brains required longer impregnation times for better staining. Although every factor had a role in determining optimal neuronal staining, impregnation time and the pH of staining solutions were key factors among them. This modified Golgi-Cox protocol provides a simple and economical procedure to stain both neurons and glia separately.

Performances of metals modified activated carbons for fluoride removal from aqueous solutions

The present research work focused on the activated carbon (AC) preparation from dates waste followed by its surface modification by incipient wetness impregnation using different metals: Ca, Co, Mg and Al. The obtained results showed that the AC-Al presented the best removal efficiency of the fluoride. The prepared activated carbons (AC) and (AC-Al) were characterized by several techniques. The optimization study of the AC-Al impregnation conditions was investigated by varying the impregnation time and the Al loading. Batch experiments were carried out to investigate the effect of certain operating parameters on the removal percentage. Several isotherm models were applied.

Preparation of Sb2O3/Sb2S3/FeOOH composite photoanodes for enhanced photoelectrochemical water oxidation

Abstract A novel Sb2O3/Sb2S3/FeOOH photoanode was fabricated via a simple solution impregnation method along with chemical bath deposition and post-sulfidation. The X-ray diffractometry, Raman measurement, and X-ray photoelectron spectroscopy show that the Sb2O3/Sb2S3/FeOOH thin films are successfully prepared. SEM−EDS analyses reveal that the surface of Sb2O3/Sb2S3 thin films becomes rough after the immersion in the FeCl3 solution. The optimized impregnation time is found to be 8 h. The FeOOH co-catalyst loaded Sb2O3/Sb2S3 electrode exhibits an enhanced photocurrent density of 0.45 mA/cm2 at 1.23 V versus RHE under simulated 1 sun, which is approximately 1.41 times compared to the photocurrent density of the unloaded one. Through the further tests of UV−Vis spectroscopy, the electrochemical impedance spectra, and the PEC measurements, the enhancement can result from the increased light-harvesting ability, the decreased interface transmission impedance, and the remarkably enhanced carrier injection efficiency.

Lansoprazole loading of polymers by supercritical carbon dioxide impregnation: Impacts of process parameters

This is the first work to load HPMC and PVP by the lansoprazole (LPZ) through supercritical solvent impregnation (SSI). The process was carried out at laboratory scale under various sets of conditions in terms of pressure (150−250 bar), temperature (308−328 K), and impregnation time (60−180 min). The results showed that an increase in any of the investigated parameters increased the drug loading, and that the temperature imposed the strongest effect on the drug loading. Moreover, impregnation loadings onto the PVP and HPMC were found to range from 0.56% to 0.61% and from 1.16% to 1.30%, respectively. For both polymers, the best results were obtained at a pressure of 250 bar and a temperature of 328 K with an impregnation time of 180 min. The processed drug was further investigated by XRD, SEM, DSC, FTIR, and DLS analyses. The final results indicated superior loading of the drug onto the HPMC rather than the PVP.